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RUN-OFFIRUN-ON FACILITIES The NCRC&SL utilizes several facilities to control run-on and run-off. A perimeter berm around the waste management unit prevents any run-on to the unit. This perimeter berm, along with a series of ditches, also controls all surface run-off during storm events, and directs surface run-off from the landfill to a retention basin on the east side of the site(Figure 3). The primary path for water entering the site is from a tributary of South Paddy Creek east of the site. Water entering from this source is diverted into the wetlands on the north end of the site and around the unit(Figure 3). There were no breeches in any of the run-on/run-off facilities during this semester. These facilities will continue to be monitored. LEACHATE COLLECTION AND RECOVERY SYSTEM Leachate is collected in the Leachate Collection and Recovery Systems (LCRSs) of the three landfill Areas. This leachate is returned to the refuse in accordance with the WDRs for this site. Landfill gas condensate is pumped into the LCRS of Area 4, and is handled as leachate also in accordance with the WDRs. The semi-arid climate of the North County Landfill and the waste shed from which the refuse is collected provides dry refuse in which the leachate can be absorbed. Leachate quantities do not indicate significant intrusion of water, or difficulty in meeting regulatory limits. Normal operation of the leachate system at the North County Landfill provides redundancy in absorption. Leachate may be pumped to the deep infusion points, to a leachate storage tank,to the active landfill face if the active face is over Area 3,4, or other future lined Areas. Facilities The leachate facilities for each Area include: ■ Sump with dedicated leachate pump. ■ Volumetric flow meter for the sump pump, indicating total gallons pumped(the meter for Area 4 also indicates instantaneous flow rate). ■ A leachate storage tanks. These tanks are normally not in use but are available if leachate cannot be returned to the refuse directly from the sump. o Areas 1 and 3 sumps share one tank(3,000 gallons) o Area 4 is provided with a separate tank(12,000 gallons). ■ Float switches within each leachate tank activate alarms based on high or low level conditions. o Under high-level conditions,the leachate sump pump are deactivated. This prevents overflow of the tanks. o Under low-level conditions, pumps that can remove leachate from the tanks are deactivated,preventing the operation of these pumps with insufficient fluid. Transfer pumps at each leachate tank which can deliver leachate into a water truck if needed. North County RC&SL Public Works/Solid Waste 2nd Semester and Annual 2013 Groundwater Monitoring 13 County of San Joaquin—January 25,2014